In addition, webcomics like Gunnerkrigg Court, Unsounded, or Kill Six Billion Demons are at an advantage over webcomics like Girl Genius or Erfworld - the writer is the artist, so they can be thinking of the plot line while sketching and vice versa, and they don't need to split comic income across two or more households.
Erfworld has had Jamie for Book 1, Xin for Book 2, David for the first half of Book 3, Xin+Lauri, for the second half, and now Xin+? for Book 4.
There's also one misconception I've seen about the $1800 per online update - the team don't get that as a lump sum. Instead it's effectively store credit for the merchandise, so whatever % profit they make off the books etc. would be their real income from it.